1. Field of the Invention
The present invention relates to a collision determination apparatus for a vehicle, more particularly relates to a vehicle collision determination apparatus that determines an occurrence of a collision based on a pressure change in a bumper of the vehicle.
2. Description of Related Art
Passenger protection systems for a vehicle have been put to practical use. A typical passenger protection system detects a collision between a vehicle and an object, and activates a passenger protection apparatus such as an airbag and the like to protect a passenger of the vehicle. JP-2007-126014A corresponding to US Patent Application Publication No. 2007/0106474 proposes a technique for minimizing malfunction of the passenger protection system in case of a failure of a sensor for vehicle collision detection. According to the technique, the system includes a safing sensor in addition to a main sensor to provide redundancy, and activates the passenger protection apparatus based on a result of a logical product, in other words, AND operation, of a value associated with the output of the main sensor and that of the safing sensor.
Pedestrian protection systems for a vehicle have been proposed. For example, JP-2006-117157A corresponding to US Patent Application Publication No. 2006/0087417 proposes a pedestrian protection system that includes a chamber member and a pressure sensor. The chamber member is arranged in an absorber part in a bumper of the vehicle, and defines therein a chamber space. When a collision between a vehicle and an object deforms the chamber member, the pressure senor senses a pressure change of the chamber space to identify a type of the colliding objects. When the colliding object is identified as a pedestrian, the pedestrian protection system activates a pedestrian protection apparatus such as an active hood system and an airbag on a cowl to protect the pedestrian against the collision. Practical application of this type of pedestrian protection systems is under review.
The inventors consider that, to the pedestrian protection system also, it is necessary to add a safing sensor for redundancy to minimize malfunction of the system in case of sensor malfunction. However, it is found that there exists no effective proposal on it.